DC motor

A DC motor comprising:

• a rotary shaft;
• an armature core having a plurality of salient poles and secured to said rotary shaft;
• armature windings coiled on said salient poles;
• a commutator electrically connected to said windings and secured to said rotary shaft;
• switch means capable of cutting off the current flow path to said windings and disposed between said salient poles of said core and operable to be opened and closed by centrifugal force in a plane containing the axis of said rotary shaft, said switch means being electrically connected in the current flow path to said windings;
• a distributing board having electrical means for extinguishing any spark produced by said commutator and said switch means, said distributing board being disposed with respect to said windings on the same side that said commutator is disposed;
• said commutator being electrically connected to said electrical means;
• and
• means for supporting said switch means between the salient poles of said core and disposed with respect to said windings on the same side tht said commutator is disposed, said support means including:
• means for electrically connecting said switch means in the current flow path to said windings and to said electrical means of said distributing board, said means being electrically connected to said switch means.

A DC motor comprising:

• a rotary shaft;
• an armature core having a plurality of salient poles and secured to said rotary shaft, said core being formed of soft magnetic material;
• armature windings coiled on said salient poles of said core;
• a commutator electrically connected to said windings and secured to said rotary shaft, said commutator including:
• a plurality of conductor pieces provided correspondingly to said windings and electrically connected thereto;
• switch means capable of cutting off the current flow path to said windings and disposed between said salient poles of said core and operable to be opened and closed by centrifugal force in a plane containing the axis of said rotary shaft, said switch means being electrically connected in the current flow path to said windings, said switch means including:
• first and second contacts held in engagement by elastic force and electrically connected in the current flow path to said windings;
• and
• conductive elastic members for holding said first and second contacts in engagement, said elastic members supporting said first contacts and being electrically connected thereto;
• a distributing board having first electrical means for extinguishing any spark produced by said commutator and second electrical means for extinguishing any spark produced by said switch means, said distributing board being disposed with respect to said windings on the same side that said commutator is disposed, said first electrical means being electrically connected between the conductor pieces of said commutator;
• means for supporting said switch means and including:
• first nonconductive members formed in an annular shape centered about the axis of said rotary shaft, said first nonconductive members being disposed with respect to said windings on the same side that said commutator is disposed;
• second nonconductive members projectedly provided between said salient poles and secured to said first nonconductive members;
• first conductive members supporting the elastic members of said switch means and held by said first nonconductive members;
• and
• second conductive members supporting said second contacts of said switch means and held by said second nonconductive members;
• the first and second contacts of said switch means being electrically connected in the current flow path to said windings and to said second electrical means of said distributing board through said first and second conductive members of said support means.

A DC motor comprising:

• a rotary shaft;
• an armature core having a plurality of salient poles and secured to said rotary shaft, said core being formed of soft magnetic material;
• armature windings coiled on said salient poles of said core;
• a commutator electrically connected to said windings and secured to said rotary shaft, said commutator including:
• a plurality of conductor pieces provided correspondingly to said windings and electrically connected thereto;
• switch means capable of cutting off the current flow path to said windings and disposed between said salient poles of said core and operable to be opened and closed in a plane containing the axis of said rotary shaft, said switch means being electrically connected in the current flow path to said windings;
• means for supporting said switch means between said salient poles of said core and disposed with respect to said windings on the same side that said commutator is disposed, said support means including means for electrically connecting said switch means in the current flow path to said windings and electrically connected to said switch means;
• and
• a printed distributing board disposed with respect to said windings on the same side that said commutator is disposed, said distributing board including:
• first electrical means for extinguishing any spark produced between the conductor pieces of said commutator;
• first conductive portions provided correspondingly to said conductor pieces of said commutator and electrically connected to said first electrical means, said conductor pieces of said commutator being electrically connected to said first conductive portions;
• second electrical means for extinguishing any spark produced by said switch means;
• and
• second conductive portions provided correspondingly to the means in said support means for connecting said switch means, said second conductive portions being electrically connected to said second electrical means, said connecting means being electrically connected to said second conductive portions.

A revolution speed control device in a DC motor provided with a rotary shaft, an armature core having a plurality of salient poles and secured to said rotary shaft, armature windings coiled on said salient poles of said core, and a commutator secured to said rotary shaft and electrically connected to said windings, said device comprising:

• switch means capable of cutting off the current flow path to said windings and disposed between said salient poles of said core and operable to be opened and closed by centrifugal force in a plane containing the axis of said rotary shaft, said switch means being electrically connected in the current flow path to said windings, said switch means including:
• first and second contacts held in engagement by elastic force and electrically connected in the current flow path to said windings;
• and
• conductive elastic members for holding said first and second contacts in engagement, said elastic members supporting said first contacts and being electrically connected thereto;
• means for supporting said switch means and including:
• first nonconductive members formed in an annular shape centered about the axis of said rotary shaft, said first nonconductive members being disposed with respect to said windings on the same side that said commutator is disposed;
• second nonconductive members projectedly provided between said salient poles and secured to said first nonconductive members;
• first conductive members supporting the elastic members of said switch means and held by said first nonconductive members;
• and
• second conductive members supporting said second contacts of said switch means and held by said second nonconductive members;
• said first and second conductive members being electrically connected in the current flow path to said windings.